Evaporative cooling system for hydrostatic cooker

ABSTRACT

An evaporative cooling system for a hydrostatic cooker having an endless conveyor for moving rows of hot containers along a vertical zig-zag path through a vertically elongated cooling chamber. The system includes a plurality of vertically spaced troughs for directing cooling water against hot containers being processed, a sump for collecting the cooling water, pumps for recirculating the cooling water from the sump to the troughs, and means for adding make-up water to the sump. The system also includes a high volume-low velocity exhaust fan mounted on the upper end of the cooling chamber for drawing air upwardly through the cooling chamber to reduce the pressure within the cooling chamber below atmospheric and thereby increase the rate of evaporative cooling to such an extent that the cooling temperature becomes stable and make up water is required only to compensate for water loss through evaporation.

United States Patent [is] 3,661,201 Bash et al. 1 May 9, 1972 [54] EVAPORATIVE COOLING SYSTEM 7 Primary Examiner-Edward G. Favors FOR HYDROSTATIC COOKER Attorney-F. W. Anderson, C. E. Tripp and A. J. Moore [5 7] ABSTRACT An evaporative cooling system for a hydrostatic cooker having an endless conveyor for moving rows of hot containers along a vertical zig-zag path through a vertically elongated cooling chamber. The system includes a plurality of vertically spaced troughs for directing cooling water against hot containers being processed, a sump for collecting the cooling water, pumps for recirculating the cooling water from the sump to the troughs, and means for adding make-up water to the sump. The system also includes a high volume-low velocity exhaust fan mounted on the upper end of the cooling chamber for drawing air upwardly through the cooling chamber to reduce the pressure within the cooling chamber below atmospheric and thereby increase the rate of evaporative cooling to such an extent that the cooling temperature becomes stable and make up water is required only to compensate for water loss through evaporation.

4 Claims, 1 Drawing Figure PATENTEUHAY 9 1912 Lg j:

INVENTORS WINSTON D. BASH FRANK 0. HIGKEY -ATTY.

AGENT EVAPORATIVE COOLING SYSTEM FOR I'IYDROSTATIC COOKER BACKGROUND OF THE INVENTION 1. Field of the Invention This invention pertains to the cooker art and more particularly relates to an evaporative cooling system for hydrostatic cookers.

2. Description of the Prior Art Hydrostatic cookers having cascading water cooling systems with a blower at the base of the cooling chamber which increases the pressure within the cooling chamber are known. Such a system is disclosed in US. Pat. No. 3,031,065 which was issued to John F. French on Apr. 24, l962 and is assigned to the assignee of the present invention.

Cooling systems having blowers at the base of the cooling chamber have certain disadvantages. Since the air is being pushed into the cooling chamber at high velocity, rather than being pulled therefrom, the high velocity air discharged from the blower tends to channel as it moves upwardly through the cooling chamber and accordingly is not distributed evenly throughout the cooling chamber. Although this situation can be improved by providing a plurality of small base mounted blowers, this is not economical and does not fully correct the channeling problem. Thus, the rate of evaporation is not as high as it could be since the air within the areas of the cooling chamber that are bypassed by the main flow of air from the blower tends to become saturated.

Another difficulty with a base mounted blower is that the blower pushes air into the cooling chamber rather than drawing the air out of the upper end. The pressure within the chamber is therefore greater than the atmospheric pressure and accordingly lowers the rate of evaporation since the rate of evaporation increases as the pressure reduces.

It has also been determined that when the prior art base mounted blowers are used, condensate tends to fall onto the blowers thus damaging the equipment, especially the electric drive motors. An additional difficulty occurs during operation in winter since ice tends to form on the base mounted equipment.

SUMMARY OF THE INVENTION The evaporate cooling system of the present invention includes a single high volume-low velocity exhaust fan disposed on top of the cooling chamber of a hydrostatic cooker having an endless processing conveyor for carrying rows of hot containers along a vertical zig-zag path. Cooling water is pumped from a sump at the base of the cooling chamber to a plurality of troughs disposed alongside the path of movement of the conveyor for discharge onto the containers as they move therepast. When using a single 60,000 cubic feet per minute exhaust fan in a four-pass cooling chamber it has been determined that temperature controls are not needed in the cooling chamber since the temperature of the cooling water remains substantially constant and sufiiciently low to provide the desired cooling without the addition of any cold make-up water to the sump. However, a small amount of make-up water is added to the sump in order to compensate for loss of water due to evaporation and removal from the system by the exhaust fan.

BRIEF DESCRIPTION OF THE DRAWING The drawing is a diagrammatic vertical section of a hydrostatic cooker having the evaporative cooling system of the present invention associated therewith, the central portion of the hydrostatic cooker being cut away.

DESCRIPTION OF THE PREFERRED EMBODIMENT The evaporative cooling system of the present invention is associated with a hydrostatic cooker 12 of well known design. The hydrostatic cooker 12 comprises a frame 13 that includes a pair of spaced vertical walls 14 (only one being shown) that are supported in spaced parallel relationship. A housing 16 which extends between the two walls 14 has a closed upper end 18 and two depending walls 20 and 22 which cooperate with the two walls 14 to define a cooking chamber 24 which is filled with steam from a valved conduit 25 at a predetermined cooking temperature and pressure, for example, at about 250 F to 275 F and 15 to 20 psi gauge. The lower end of the housing 16 opens into a water filled trough or chamber 26 which is formed by the two walls 14, a transverse horizontal plate 28 and the lower end portions of two transverse vertical walls 30 and 32. The wall 30 cooperates with another transverse wall 34 to define an inlet hydrostatic water leg 36, and the wall 32 cooperates with a transverse vertical wall 38 to provide an outlet hydrostatic leg 40. The hydrostatic legs 36 and 40 communicate with the chamber 26 and are filled with water from valved conduits 41 and 42 so as to create sufficient hydrostatic pressure to resist the pressure of steam within the cooking chamber 24. The inlet hydrostatic water leg 36 is thermostatically controlled to provide a gradually increasing water temperature from approximately 210 F at its upper end to approximately the sterilizing temperature in the steam chamber at its lower end. The outlet water leg 40 is also thermostatically controlled to provide a gradually decreasing temperature from approximately the sterilizing temperature at its lower end any suitable temperature below the boiling point of water at its upper end. Steam is added to the water in the hydrostatic inlet leg 36 to provide the desired temperature therein, and cooling water is directed into the outlet or cooling leg 40 by conduit 42 and heated water may be drained therefrom by valved conduit 43 to provide the desired cooling temperature therein.

A cooling chamber 50 of the evaporative cooling system 10 is defined by the walls 14, the vertical wall 32 which is preferably insulated, a roof 54, an end wall 56, and a partial floor 58.

A coolant sump 60 is defined by the walls 14, the lower portion of the end wall 56, a short vertical wall 62, and a floor 64 all connected together in fluid tight engagement. Make-up cooling water is directed into the sump 60 as required by a valved conduit 66.

An endless processing conveyor 68 having elongated carriers 70 of standard design thereon is trained around a plurality of sprockets 72 secured to shafts 74 joumaled near the upper end of the cooker and is guided along its path of movement by guide rails (not shown). The conveyor is continuously driven by a motor M which is connected to at least one of the shafts 74 by a chain drive 76. Rows of containers C to be processed are fed into the carriers 70 at a feed station F5 in a well known manner, and after these containers have been cooked and cooled, they are discharged from the cooker 12 at a discharge station DS in the usual manner.

The conveyor 68 makes five vertically elongated runs or passes through the cooling chamber 50. While the hot containers C and carriers are moving along these vertical runs, cooling water is discharged thereagainst from four vertical series of troughs 80, 82, 84 and 86. The troughs are supported by the walls 14 and have one or more series of holes 87 in their lower portions which are angled to direct the cooling water against the adjacent run of the conveyor 68. Downwardly inclined deflectors 88, 90 and 92 are disposed between adjacent troughs 80, 82, 84 and 86, respectively, in the vertical series of troughs and serve to deflect cooling water which splashes off the carriers toward the containers thus preventing free fall of the cooling water to the base of the cooling chamber 50. Cooling water is collected in the sump 60 and is recirculated to the troughs by pumps P1, P2 and P3 and conduits 94, 96 and 98, respectively. The conduits 98 and 96 are connected to the troughs and 82, respectively, while the conduit 94 is connected to the troughs 84 and 86. Float valves or the like (not shown) are associated with each trough and its conduit so as to control the amount of cool water entering each trough. Most of the water discharged from the troughs against the rows of containers C and carriers 70 moving therepast eventually falls to the partial floor 58 and drains into the sump 60 for recirculation.

In order to improve the rate of cooling, an exhaust fan 102 is mounted on a hood 104 that is supported on the roof 54 of the cooling chamber 50 and communicates with the interior of the chamber through a large opening 106 in the roof. The exhaust fan 102 may be of the type manufactured by Lau Blower Company, Lebanon, Ind., and designated by Model No. BT- 60-2812-07. The exhaust fan 102 preferably has a capacity of about 60,000 cubic feet per minute and includes a 60 inch diameter fan that is driven by a horse power motor M.

in order to assure an adequate flow of air upward through the cooling chamber 50, air enters the cooling chamber through three air inlet ports 108 formed in each wall 14 near the bottom of the cooling chamber 50, and also enters through an elongated opening 110 through which the conveyor 68 passes, which conveyor is about 8 feet wide. The total area of I such openings when combined is about 35 square feet.

In operation, the motors M and M are started and rows of containers C are loaded into the carriers 70 of the conveyor at the feed station FS. These containers are moved through the inlet hydrostatic leg 36, the cooking chamber 24, the cooling hydrostatic leg 40, and then enters the cooling chamber 50. At this time the temperature of the containers is slightly below 2 12 F.

The pumps P1, P2 and P3 circulate cooling water from the sump 60 to the troughs 80, 82, 84 and 86. This cooling water is then cascaded upon the containers and upon the bafiles 88, 90, and 92, and is eventually collected in the sump 60 and recirculated. It will be appreciated that each l F raise in temperature of the cascading water will absorb only 1 btu of heat per pound of water, whereas each pound of water which is induced to change state from a liquid to a vapor by evaporation will absorb 970 btus of heat.

It has been determined that with the fan operating and with a product load of about 700 pounds of containers per minute, that only about 7 gallons per minute of make-up water was required to be delivered by the conduit 66 into the sump 60. After the containers were moved through the first two vertical runs or passes in the cooling chamber 50 the temperature of the containers was reduced to below about 1 10 F. After the third and fourth pass, the temperature lowered to below an acceptable 102 F and the water in the sump was also stabilized at 102 F. It was also determined that temperature controllers were not needed in the cooling system since the 7 gpm of water was required only to make-up for water lost by evaporation and was not needed to lower the temperature of the water in the sump.

When making a comparison test with the exhaust fan 102 turned off and with the upper end of the cooling chamber 50 blocked to simulate a closed cooling system, it was determined that about 165 gpm of make-up water was required to maintain a sump temperature of about 108 F when handling a product load of 675 pounds of containers per minute. After the first two passes through the cooling chamber 50 the temperature of the containers was about 120 F, and after the third and fourth pass the temperature was reduced to about 1 F.

In view of the two above mentioned tests, it becomes apparent that when the hydrostatic cooker has a five pass cooling chamber as illustrated, use of the cooker with the 60,000 cfm exhaust fan 102 operating will require no temperature controls in the cooling system, will cool the contents to a sump temperature of about 102 F when using only four of the available five passes, and will require only enough make-up water to compensate for that lost during evaporation, i.e., about 7 gallons per minute. Moreover, when using the exhaust fan and only about 7 gpm make-up water the containers are cooled to a lowered temperature (about 110 F) after making only two passes through the cooling chamber 50, whereas under substantially the same sterilizing and product load conditions but with the exhaust fan not operating, four passes will only reduce the temperature of the containers to about 1 15 F when using about 23 times as much cooling water gpm From t e foregoing description it is apparent that the evaporative cooling system of the present invention includes a high capacity-low velocity exhaust fan mounted on the top of a cooling chamber and lowers the pressure within the cooling chamber. Cascading water in the cooling chamber is directed onto containers to be cooled and is collected in a sump and subsequently recirculated by pumps. Since air is being pulled or drawn through the cooling chamber, the pressure within the chamber is below atmospheric pressure thereby additionally inducing the liquid coolant to change state and evaporate. The rate of evaporation is sufficient to preclude the need of temperature controllers and requires only enough make-up water to replace the cooling water that is lost by evaporation.

Although the best mode contemplated for carrying out the present invention has been herein shown and described, it will be apparent that modification and variation may be made without departing from what is regarded to be the subject matter of the invention.

We claim:

1. An evaporative cooling system for a cooker of the type comprising means defining an elongated cooling chamber having an air entrance port near one end, conveying means for advancing hot containers to be cooled through said chamber, means for directing cooling water against the containers, and an air exhaust port at the other end of the chamber; the improvement comprising an exhaust fan at said other end of said chamber for drawing air through said entrance port and through said cooling chamber for increasing evaporative cooling by reducing the pressure within said cooling chamber to a pressure below atmospheric pressure, means for collecting and recirculating the cooling water, and means for adding a quantity of makeup water to said cooling water just sufficient to compensate for the loss of water due to evaporation and removal by said fan.

2. The cooling system of claim 1 wherein said cooling chamber is vertical with the air inlet means near the bottom and the fan at the upper end of the chamber.

3. A method of cooling containers passing through an elongated cooling chamber having an air vent near one end and wherein cooling water is directed against the containers and the water is collected and recirculated; the improvement comprising mechanically exhausting gases including water vapor from the other end of the cooling chamber while reducing the pressure within the cooling chamber to a pressure below atmospheric pressure for inducing the cooling water to evaporate, and adding a quantity of make-up cooling water to the recirculated water substantially equal to the quantity of water removed as vapor by said gas exhausting step.

4. in a hydrostatic cooker of the type having an endless container carrier conveyor that passes up from a feed and discharge station, down through a water leg, up and down through a steam leg, up through a water leg, up and down through a water spray evaporative cooling chamber having upper carrier sprockets, said chamber having a bottom wall portion for catching water, said conveyor passing back to the feed and discharge station; the improvement wherein said cooling chamber has a partial floor above said water catching portion that provides a conveyor opening adjacent the outside wall of the cooling chamber, air inlet means for said cooling chamber above said partial floor, a hood connected to the walls of said cooking chamber above said upper carrier sprockets, an exhaust fan in said hood, and means driving said exhaust fan at a rate sufficient to reduce the pressure in said cooling chamber to a pressure below atmospheric pressure. 

1. An evaporative cooling system for a cooker of the type comprising means defining an elongated cooling chamber having an air entrance port near one end, conveying means for advancing hot containers to be cooled through said chamber, means for directing cooling water against the containers, and an air exhaust port at the other end of the chamber; the improvement comprising an exhaust fan at said other end of said chamber for drawing air through said entrance port and through said cooling chamber for increasing evaporative cooling by reducing the pressure within said cooling chamber to a pressure below atmospheric pressure, means for collecting and recirculating the cooling water, and means for adding a quantity of make-up water to said cooling water just sufficient to compensate for the loss of water due to evaporation and removal by said fan.
 2. The cooling system of claim 1 wherein said cooling chamber is vertical with the air inlet means near The bottom and the fan at the upper end of the chamber.
 3. A method of cooling containers passing through an elongated cooling chamber having an air vent near one end and wherein cooling water is directed against the containers and the water is collected and recirculated; the improvement comprising mechanically exhausting gases including water vapor from the other end of the cooling chamber while reducing the pressure within the cooling chamber to a pressure below atmospheric pressure for inducing the cooling water to evaporate, and adding a quantity of make-up cooling water to the recirculated water substantially equal to the quantity of water removed as vapor by said gas exhausting step.
 4. In a hydrostatic cooker of the type having an endless container carrier conveyor that passes up from a feed and discharge station, down through a water leg, up and down through a steam leg, up through a water leg, up and down through a water spray evaporative cooling chamber having upper carrier sprockets, said chamber having a bottom wall portion for catching water, said conveyor passing back to the feed and discharge station; the improvement wherein said cooling chamber has a partial floor above said water catching portion that provides a conveyor opening adjacent the outside wall of the cooling chamber, air inlet means for said cooling chamber above said partial floor, a hood connected to the walls of said cooking chamber above said upper carrier sprockets, an exhaust fan in said hood, and means driving said exhaust fan at a rate sufficient to reduce the pressure in said cooling chamber to a pressure below atmospheric pressure. 